1. Field of the Invention
The present invention is generally directed to wireless communication systems. In particular, the present invention is related to a system, method and apparatus for the wireless communication of analog and/or digital information from a generalized content source to a generalized content sink.
2. Background
Wireless interfaces offer a compelling value proposition for the transfer of photos, music, video, data and other forms of media content amongst networked consumer electronics, personal computers (PCs), and mobile devices throughout the home. The promise of simple and inexpensive installation coupled with the potential elimination of bulky and unsightly cables has created a buzz throughout the industry. Seeing this opportunity, technology vendors have rushed to develop and position Bluetooth™, 802.11 WiFi®, and 802.15.3a Ultra Wide Band (UWB) for emerging in-home content transfer applications as these wireless techniques offer adequate coverage area, throughput, and quality levels for generic content transfer.
Media content transfer is not the only in-home wireless application, however, and it may not even be the most appealing one for the consumer. Many industry analysts are projecting that high-performance digital cable replacement may, in fact, be the more lucrative in-home opportunity for wireless technology.
For example, most high-definition plasma/LCD displays, digital projectors, and DVD players being introduced in the market today include a high-definition media interface (HDMI) connector to facilitate the high-fidelity transfer of digital content from source devices (e.g. digital set top boxes, DVD players, etc.) to display devices via digital cable. The HDMI interface standard supports all common high-definition formats including 720p and 1080i high-definition television (HDTV) which require data rates of 1.5 Gbps at a bit error rate (BER) of 10−9. HDMI also incorporates the Motion Picture Association of America (MPAA)-approved High-bandwidth Digital Content Protection (HDCP) which ensures the security of the digital content as it is transferred between source and display. The comprehensively designed HDMI standard has garnered widespread industry support and sales of HDMI equipped units is projected to grow from 50 million in 2005 to over 200 million in 2008.
Technology vendors are attempting to position 802.11 and UWB as candidate solutions for digital cable replacement. Unfortunately, the coverage area, throughput, and quality levels for 802.11 and UWB are woefully inadequate to serve as a replacement for the demanding high-performance digital cable market, particularly that related to 720p and 1080i HDTV. For example, the wireless replacement of the HDMI cables requires 7-10× greater throughput and 1000× better quality than what 802.11 and UWB were designed to provide.
By way of illustration, generic content transfer techniques share the following characteristics: shared multiple access communication, a 1% BER, latency acceptance, transfer of compressed data, use of retransmissions, and support for data rates up to 200 Mbps. In contrast, data transfer over high-performance digital cable is characterized by: dedicated point-to-point communication, 10−9 BER, low latency, transfer of uncompressed data, best effort communication (i.e., no retransmissions), and support for data rates in excess of 1 Gbps. Thus, existing wireless technologies such as 802.11 and Bluetooth along with proposed UWB solutions fail to provide the throughput and quality needed for in-home high-performance digital cable replacement.
Currently, 802.15.3a UWB is being touted as a solution to both generic content transfer and wireless HDMI cable replacement. Unfortunately, because of the emphasis on generic content transfer applications, 802.15.3a UWB performance falls dramatically short of what is required for wireless HDMI cable replacement. For instance, the maximum 802.15.3a data rate will be restricted to roughly 200 Mbps with potentially large data transfer latencies. 802.15.3a contains a general purpose media access control (MAC) that cannot exploit the inherent data rate asymmetries associated with HDMI where the display to source backchannel data rate requirement is negligible relative to the source to display forward channel—as a result overall throughput suffers. Even more troubling is the 802.15.3a acceptance of a 1% BER (8% packet error rate (PER)) which has potentially disastrous quality implications that could impact consumer acceptance of wireless cable replacement products.
So while 802.15.3a certainly addresses the needs of generic content transfer applications, it falls far short of the data rates and error performance required for wireless HDMI cable replacement. Many have focused on compressing digital content using MPEG-2 to overcome the data rate limitations of 802.15.3a, but the cost associated with adding MPEG-2 encoders to source devices makes this impractical. Even if cost constraints could be overcome, transmission of MPEG-2 encoded video is one of the most demanding applications in terms of quality of service (QoS). MPEG-2 can not tolerate large variations on delays such as those introduced by the 802.15.3a MAC layer and MPEG-2 quality is severely degraded when BER approaches 10−5, far below the 1% BER target of 802.15.3a.
What is needed then, is a system, method and apparatus for the wireless delivery of content from a generalized content source to a general content sink. The proposed solution should perform in a manner that is sufficiently secure and robust to serve as a replacement for the delivery of HDMI content over cable. The solution should also be applicable to the delivery of other types of content traditionally delivered over cable, including but not limited to Digital Video Interface (DVI) content, composite video (CVSB) content, S-video content, RGB video content, YUV video content, and/or various types of audio content.